Let's not make the same mistake that was made in the US:
The people who - rightfully - lost respect for the US and now consider it an adversary are German diplomats, politicians and the press. But the ones with the voting power are the German public. And if German voters are anything like American voters, there may be a deep disconnect between them and the elites.
And so despite the outrage of the people who know better, the German population might just as easily vote for fascists in Germany as they did in the US.
My point being, we'll know if Vance's speech backfired when the German elections are over. I'm not so optimistic that it did.